The prior art contains disclosures and teachings of sealed track joints for crawler tractors or the like, and examples thereof are found in U.S. Pat. Nos. 2,911,840; 3,336,086; 3,347,602; 3,680,924; and 3,731,551. The last aforesaid patent somewhat epitomizes the prior art to the extent that the prior art discloses a sealed track joint wherein there is an elastomeric seal which is compressed between links and adjacent a bushing surface for sealing at that location in the joint.
The present invention provides an improvement in a sealed track joint in that it presents a sealed joint which effectively and positively provides a seal in a plurality of locations along the path of potential entry of foreign matter into the joint. Further, the present invention provides the seal in a simplified and inexpensive form and wherein the seal is efficient and reliable and has a long life and is also self-adaptable to the surrounding parts of the joint to thus be self-sealing as required and to adjust itself to the movement of the surrounding parts while retaining its efficient sealing function.
More specifically, the sealed joint of this invention provides an elastomeric seal member which presents a plurality of locations of sealing areas along each of the two or more surfaces which are inherently presented in a track joint and along which foreign matter may enter the joint. Accordingly, the track joint of this invention accomplishes the aforementioned objectives and effectively maintains the joint free of foreign matter so that dirt and the like cannot enter the joint. In addition to the desirable results of sealing at two or more locations along any potential entry surface for dirt, the seal of this invention will continue to effectively preclude the entry of dirt even though a portion of the seal were to rupture or to otherwise fail, and such rupture or failure is not at all likely or probable even though the seal is subjected to the usual torsional stresses created by the relative movement of the part surrounding the seal. That is, a track joint commonly has its links pivotal about the axis of the joining pin, and any seal which is disposed in contact with and between the pivoting links is thus subjected to either the sliding action of the links or to the torsional stress induced by the movement of the links. In the present invention, the seal is also arranged to withstand the torsional forces and to avoid failure or rupture in withstanding those forces, and the seal continues to be highly effective in precluding the entry of dirt or the like past the seal even though the seal is disposed between the links moving relative to each other.
Still further, the sealed track joint of the present invention provides an arrangement wherein the seal is automatically and snugly disposed in its effective sealing position in the course of the usual assembly of the joint, namely, the pressing of the track links onto the joint bushing and onto the joint pin. In that assembly process, the seal is automatically positioned and compressed and is consequently retained in its desired and effective sealing position. Also, the joint of this invention is arranged with the seal having the attributes as mentioned above and wherein the seal can withstand torsional stresses, by flexing and adjusting to the movement of the parts in contact with the seal, and, when the movement of the adjacent parts is of a sufficient magnitude, then the seal will again accommodate that movement by retaining its position while the parts slide over the seal, and the seal will still maintain its function and efficient qualities of precluding the entry of contaminants into the joint.
Other objects and advantages will become apparent upon reading the following description in light of the accompanying drawings.